title: Chicken HSP70 DNA vaccine inhibits tumor growth in a canine cancer model.
abstract: Immunization with xenogeneic DNA is a promising cancer treatment to overcome tolerance to self-antigens. Heat shock protein 70 (HSP70) is over-expressed in various kinds of tumors and is believed to be involved in tumor progression. This study tested a xenogeneic chicken HSP70 (chHSP70) DNA vaccine in an experimental canine transmissible venereal tumor (CTVT) model. Three vaccination strategies were compared: the first (PE) was designed to evaluate the prophylactic efficacy of chHSP70 DNA vaccination by delivering the vaccine before tumor inoculation in a prime boost setting, the second (T) was designed to evaluate the therapeutic efficacy of the same prime boost vaccine by vaccinating the dogs after tumor inoculation; the third (PT) was similar to the first strategy (PE), with the exception that the electroporation booster injection was replaced with a transdermal needle-free injection. Tumor growth was notably inhibited only in the PE dogs, in which the vaccination program triggered tumor regression significantly sooner than in control dogs (NT). The CD4(+) subpopulation of tumor-infiltrating lymphocytes and canine HSP70 (caHSP70)-specific IFN-γ-secreting lymphocytes were significantly increased during tumor regression in the PE dogs as compared to control dogs, demonstrating that specific tolerance to caHSP70 has been overcome. In contrast, no benefit of the therapeutic strategy (T) could be noticed and the (PT) strategy only led to partial control of tumor growth. In summary, antitumor prophylactic activity was demonstrated using the chHSP70 DNA vaccine including a boost via electroporation. Our data stressed the importance of DNA electroporation as a booster to get the full benefit of DNA vaccination but also of cancer immunotherapy initiation as early as possible. Xenogeneic chHSP70 DNA vaccination including an electroporation boost is a potential vaccine to HSP70-expressing tumors, although further research is still required to better understand true clinical potential.
authors.affiliation: Animal Cancer Center, School of Veterinary Medicine, National Taiwan University, Taipei, Taiwan, ROC.
authors.forename: Wen-Ying
authors.initials: WY
authors.lastname: Yu
authors.forename: Tien-Fu
authors.initials: TF
authors.lastname: Chuang
authors.forename: Cécile
authors.initials: C
authors.lastname: Guichard
authors.forename: Hanane
authors.initials: H
authors.lastname: El-Garch
authors.forename: Dominique
authors.initials: D
authors.lastname: Tierny
authors.forename: Albert Taiching
authors.initials: AT
authors.lastname: Laio
authors.forename: Ching-Si
authors.initials: CS
authors.lastname: Lin
authors.forename: Kuo-Hao
authors.initials: KH
authors.lastname: Chiou
authors.forename: Cheng-Long
authors.initials: CL
authors.lastname: Tsai
authors.forename: Chen-Hsuan
authors.initials: CH
authors.lastname: Liu
authors.forename: Wen-Chiuan
authors.initials: WC
authors.lastname: Li
authors.forename: Laurent
authors.initials: L
authors.lastname: Fischer
authors.forename: Rea-Min
authors.initials: RM
authors.lastname: Chu
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D019496:Cancer Vaccines / Q000276:immunology*; D002645:Chickens; D004285:Dogs; D018274:Electroporation; D018840:HSP70 Heat-Shock Proteins / Q000276:immunology*; D007371:Interferon-gamma / Q000276:immunology; D007694:Killer Cells, Natural / Q000276:immunology; D008969:Molecular Sequence Data; D016415:Sequence Alignment; D014611:Vaccination; D019444:Vaccines, DNA / Q000276:immunology*; D014685:Venereal Tumors, Veterinary / Q000276:immunology / Q000517:prevention & control*
chemical_list: D019496:Cancer Vaccines; D018840:HSP70 Heat-Shock Proteins; D019444:Vaccines, DNA; D007371:Interferon-gamma